i have tried to simulate the case that has been mentioned in the attached paper, a backward step flow, but when i draw the mean x-velocity profile at specific location (x/H=14), i do not get good results. i did this procedure for simulation:

1) run the case with k-e model

2) wrote this command: solve/initialize/init-instantaneous-vel (i write this command to generate the instantaneous velocity out of the steady state RANS results as Fluent manual mentioned)

3) wrote this command: solve/initialize/init-flow-statistics (i write this command to zero out the initial statistics as Fluent manual mentioned)

4) wrote (rpsetvar 'les-2d? #t) to enable on 2D LES model

5) turned on Transient

6) select LES model

7) second order model for time step

8) for perturbation i used turbulent intensity and hydrolic diameter

9) i saved data for every 1 time step and also turned on the "Data Sampling for time statistics"

10) the time step used in the paper is 0.005 but i used even smaller one :0.003

11) run the cod for 2000 time steps

when i look at mean x-vel contour, it has the fully developed format, but i do not know why the results are different from the paper. i used both outflow and pressure outlet boundary condition for outlet and also a channel with larger length (paper is 34H mine 40 H where H=26.7 mm).

i used both 34H and 40H for the simulations and i got different results for the vel. profile at x/H=14. i used 259 and 25 nodes in x and y direction respectively as paper mentioned. and Samgosinesky model.

do you have any idea? how many nodes should be used in each direction and how can i find that my results are correct?